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This report suggests a three level methodology to help identify the most promising sites for the construction of a priority lane. The three levels define a screening process through which, the operating performance of the sites is evaluated. Level I is a qualitative evaluation more appropriate as a planning tool, performed by professionals familiar with the potential sites and exercising their judgment A scoring sheet has been developed to assist them. Level II addresses operational issues both in the short and the medium term. Some simple calculations are necessary. Limited amounts of data are necessary. In the first phase of Level II, the analyst through a series of nomographs evaluates the priority and non-priority lanes immediately after their implementation, that is before any demand response occurs. The second phase of Level II accounts for the demand response that will occur in the medium term. A relatively simple analytical model is used for this phase. Level III is a comprehensive evaluation of the sites that passed successfully through Levels I and II. For this purpose, FREQ, a computer simulation model was modified to accept the design of an added priority lane. The new version, FREQ10PL is one part of the FREQ10 family. Two phases are recognized,  the short term (day+ 1) and the medium term. In the medium term demand response occurs. This includes both spatial and modal shifts. Spatial shift occurs from the arterial system to the freeway priority and nonpriority lanes. Modal shift occurs from the general purpose lanes of the freeway to the priority lanes. An investigation at Level III requires considerable resources. It is therefore best performed, with a limited number of sites.